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石田 駿一大学院工学研究科 機械工学専攻助教
研究者基本情報
■ 学位■ 研究キーワード
■ 研究分野
■ 委員歴
研究活動情報
■ 受賞- 2024年09月 日本計算力学連合, The JACM Young Investigator Award
- 2023年11月 The Asian-Pacific Association for Biomechanics, Yamaguchi Medal
- 2020年06月 第32回バイオエンジニアリング講演会Outstanding Presentation
- 2020年04月 日本機械学会, 奨励賞（研究）
- 2019年05月 第24回計算工学講演会グラフィクスアワード優秀賞
- 2019年05月 第24回計算工学講演会グラフィクスアワード特別賞（meshman賞）
- 2018年12月 第32回数値流体力学シンポジウム ベストCFDグラフィックスアワード最優秀作品賞（動画部門）
- 2018年07月 Outstanding Young Researcher Presentation, 8th World Congress of Biomechanics
- 2012年06月 第17回計算工学講演会ベストペーパーアワード
- This study evaluates gastric electrophysiology in relation to the menstrual cycle using a novel noninvasive high-resolution methodology, revealing substantial variations in gastric activity with menstrual cycling and menopause. Gastric slow-wave frequency is significantly higher in the luteal versus follicular menstrual phase. Computational modeling predicts that this difference translates to higher rates of gastric mixing and liquid emptying in the luteal phase, which is consistent with previous experimental data evaluating menstrual cycling effects on gastric emptying.American Physiological Society, 2024年07月, American Journal of Physiology-Gastrointestinal and Liver Physiology, 327(1) (1), G47 - G56[査読有り]研究論文（学術雑誌）
- Understanding the growth-induced deformation of soft materials in viscous environments is important for a variety of problems in nature and engineering. Here, we focus on the fluid–structure interaction of a hyperelastic sheet growing in an incompressible Newtonian fluid in the Stokes flow regime. We develop a computational framework for simulating this problem, where the isogeometric boundary integral method is used with the Kirchhoff–Love shell formulation and elastic–plastic decomposition of the deformation gradient tensor. We quantify the relative effects of the growth rate, the sheet bending rigidity, and the fluid viscosity on the fold formation and development of the growing sheet. Our results suggest that the viscous resistance to in-plane deformation promotes fold formation, whereas the viscous resistance to out-of-plane deformation suppresses fold development. We also investigate the effects of the thickness and aspect ratio of the rectangular sheet. Finally, we compare the growth- and prestrain-induced deformations to find a common behavior of sheets under viscous environments.AIP Publishing, 2024年05月, Physics of Fluids, 36(5) (5)[査読有り]研究論文（学術雑誌）
- Effects of magnetic field applied perpendicular to a shear plane in shear flow on the deformation of a ferrofluid droplet are numerically investigated. The boundary integral method is employed to solve the two-phase Stokes flow under a uniform magnetic field. When the magnetic field is applied perpendicular to the shear plane, the deformation of the droplet in the shear plane decreases. The magnetic field causes the droplet to elongate in the y-direction, and its cross-sectional radius in shear plane decreases. Consequently, the apparent capillary number in the shear plane decreases, thereby suppressing the droplet deformation. Droplet breakup is also suppressed by imposing a magnetic field perpendicular to the shear plane, thereby increasing the critical capillary numbers. The critical capillary numbers for the magnetic Bond numbers Bo = 2.0 and 4.0 increase to approximately 110% and 130%, respectively, than those without magnetic field. Furthermore, an equation for the theoretical prediction of the droplet deformation under a magnetic field in shear flow is presented, which is based on the small deformation theory, the decrease in the cross-sectional radius, and the boundary conditions at the droplet interface. The theoretical prediction agrees well with the numerical results for the variation in the magnetic susceptibility of the droplet as well as the viscosity ratio between the external fluid and the ferrofluid droplet under a small deformation. The critical capillary numbers under a magnetic field can also be predicted by using the numerical results without a magnetic field.AIP Publishing, 2024年03月, Physics of Fluids, 36(3) (3)[査読有り]研究論文（学術雑誌）
- Elsevier BV, 2024年03月, Journal of Fluids and Structures, 125, 104081 - 104081[査読有り]研究論文（学術雑誌）
- Elsevier BV, 2024年01月, Journal of Fluids and Structures, 124, 104022 - 104022[査読有り]研究論文（学術雑誌）
- The amplitude and frequency of peristaltic contractions are two major parameters for assessing gastric motility. However, it is not fully understood how these parameters affect the important functions of the stomach, such as gastric mixing and emptying. This study aimed to quantify the effects of peristaltic amplitude and frequency on gastric mixing and emptying using computational fluid dynamics simulation of gastric flow with an anatomically realistic model of the stomach. Our results suggest that both the increase and decrease in peristaltic amplitude have a significant impact on mixing strength and emptying rate. For example, when the peristaltic amplitude was 1.2 times higher than normal, the emptying rate was 2.7 times faster, whereas when the amplitude was half, the emptying rate was 4.2 times slower. Moreover, the emptying rate increased more than proportionally with the peristaltic frequency. The nearest contraction wave to the pylorus and the subsequent waves promoted gastric emptying. These results suggest the importance of maintaining parameters within normal ranges to achieve healthy gastric function.The Royal Society, 2023年01月, Journal of The Royal Society Interface, 20(198) (198)[査読有り]研究論文（学術雑誌）
- Peristaltic pumping is the primary mechanism of food transport in the human intestine. Intestinal contents are often modeled as power-law fluids with low-behavior indices ( n < 1). Peristaltic flows were studied for periodic contraction waves ([Formula: see text]) with infinitely long wavelengths ([Formula: see text]) in the Stokes flow regime ([Formula: see text]). However, the peristaltic flow generated by an isolated contraction wave with a short wavelength at nonzero Reynolds numbers is more relevant to physiological conditions. In this study, we investigated the peristaltic transport of a power-law fluid with a low behavior index of n = 0.21 at nonzero Reynolds numbers up to Re = 10, generated by a single short contraction wave. First, we investigated the analytical solution for the peristaltic transport of the power-law fluid for [Formula: see text] and [Formula: see text]. The analytical solution shows that the discharge flow rate of a power-law fluid generated by a single contraction wave is much smaller than that of a Newtonian fluid ( n = 1). Next, we investigated the peristaltic transport for [Formula: see text] 10 using the cumulant lattice Boltzmann method. The numerical results demonstrate that the discharge flow rate for the power-law fluid sharply increased owing to the inertia effect. The power-law fluid induces an asymmetric flow field with respect to the contraction wave at smaller Reynolds numbers than Newtonian fluids. The inertia effect was increased by the sharpness of the contraction wave. These results suggest that intestinal contents can be transported more quickly by an isolated contraction wave with a shorter wavelength when the contents have low consistency indices or when the contraction wave has a large propagation velocity.AIP Publishing, 2022年11月, Physics of Fluids, 34(11) (11), 111911 - 111911[査読有り]研究論文（学術雑誌）
- Ciliary motility disorders are known to cause hydrocephalus. The instantaneous velocity of cerebrospinal fluid (CSF) flow is dominated by artery pulsation, and it remains unclear why ciliary dysfunction results in hydrocephalus. In this study, we investigated the effects of cilia-induced surface velocity on CSF flow using computational fluid dynamics. A geometric model of the human ventricles was constructed using medical imaging data. The CSF produced by the choroid plexus and cilia-induced surface velocity were given as the velocity boundary conditions at the ventricular walls. We developed healthy and reduced cilia motility models based on experimental data of cilia-induced velocity in healthy wild-type and Dpcd-knockout mice. The results indicate that there is almost no difference in intraventricular pressure between healthy and reduced cilia motility models. Additionally, it was found that newly produced CSF from the choroid plexus did not spread to the anterior and inferior horns of the lateral ventricles in the reduced cilia motility model. These findings suggest that a ciliary motility disorder could delay CSF exchange in the anterior and inferior horns of the lateral ventricles.The Royal Society, 2022年08月, Journal of The Royal Society Interface, 19(193) (193)[査読有り]研究論文（学術雑誌）
- We investigate how ferrofluid droplets suspended in a wall-bounded shear flow can organize when subjected to an external magnetic field. By tuning the magnitude of the external magnetic field, we find that the ferrofluid droplets form chain-like structures in the flow direction when the magnetic field is weak, while forming a crystal-like pattern in a strong magnetic field. We provide the phase diagram and the critical conditions for this chain-to-crystal transition, by applying both numerical simulations and analytic calculations. We also examine how the organized patterns of the ferrofluid droplets can be controlled by simply changing the direction of the magnetic field. This work demonstrates new aspects of field-controllable ferrofluid droplets as a configurable and reprocessable metamaterial.AIP Publishing, 2022年06月, Physics of Fluids, 34(6) (6), 063309 - 063309[査読有り]研究論文（学術雑誌）
- American Physical Society (APS), 2022年06月, Physical Review Fluids, 7(6) (6)[査読有り]研究論文（学術雑誌）
- Thrombi form a micro-scale fibrin network consisting of an interlinked structure of nanoscale protofibrils, resulting in haemostasis. It is theorized that the mechanical effect of the fibrin clot is caused by the polymeric protofibrils between crosslinks, or to their dynamics on a nanoscale order. Despite a number of studies, however, it is still unknown, how the nanoscale protofibril dynamics affect the formation of the macro-scale fibrin clot and thus its mechanical properties. A mesoscopic framework would be useful to tackle this multi-scale problem, but it has not yet been established. We thus propose a minimal mesoscopic model for protofibrils based on Brownian dynamics, and performed numerical simulations of protofibril aggregation. We also performed stretch tests of polymeric protofibrils to quantify the elasticity of fibrin clots. Our model results successfully captured the conformational properties of aggregated protofibrils, e.g., strain-hardening response. Furthermore, the results suggest that the bending stiffness of individual protofibrils increases to resist extension.The Royal Society, 2021年11月, Journal of The Royal Society Interface, 18(184) (184)[査読有り]研究論文（学術雑誌）
- American Physical Society (APS), 2021年09月, Physical Review Fluids, 6(9) (9)[査読有り]研究論文（学術雑誌）
- Loss of interstitial cells of Cajal (ICC) has been associated with gastric dysfunction and is also observed during normal aging at ~13% reduction per decade. The impact of ICC loss on gastric slow wave conduction velocity is currently undefined. This study correlated human gastric slow wave velocity with ICC loss and aging. High-resolution gastric slow wave mapping data were screened from a database of 42 patients with severe gastric dysfunction (n = 20) and controls (n = 22). Correlations were performed between corpus slow wave conduction parameters (frequency, velocity, and amplitude) and corpus ICC counts in patients, and with age in controls. Physiological parameters were further integrated into computational models of gastric mixing. Patients: ICC count demonstrated a negative correlation with slow wave velocity in the corpus (i.e., higher velocities with reduced ICC; r2 = .55; p = .03). ICC count did not correlate with extracellular slow wave amplitude (p = .12) or frequency (p = .84). Aging: Age was positively correlated with slow wave velocity in the corpus (range: 25-74 years; r2 = .32; p = .02). Age did not correlate with extracellular slow wave amplitude (p = .40) or frequency (p = .34). Computational simulations demonstrated that the gastric emptying rate would increase at higher slow wave velocities. ICC loss and aging are associated with a higher slow wave velocity. The reason for these relationships is unexplained and merit further investigation. Increased slow wave velocity may modulate gastric emptying higher, although in gastroparesis other pathological factors must dominate to prevent emptying.Wiley, 2021年01月, Physiological Reports, 8(24) (24), e14659, 英語, 国際誌[査読有り]研究論文（学術雑誌）
- American Physical Society (APS), 2020年12月, Physical Review Fluids, 5(12) (12)[査読有り]研究論文（学術雑誌）
- The cerebral vasculature has a complex and hierarchical network, ranging from vessels of a few millimeters to superficial cortical vessels with diameters of a few hundred micrometers, and to the microvasculature (arteriole/venule) and capillary beds in the cortex. In standard imaging techniques, it is difficult to segment all vessels in the network, especially in the case of the human brain. This study proposes a hybrid modeling approach that determines these networks by explicitly segmenting the large vessels from medical images and employing a novel vascular generation algorithm. The framework enables vasculatures to be generated at coarse and fine scales for individual arteries and veins with vascular subregions, following the personalized anatomy of the brain and macroscale vasculatures. In this study, the vascular structures of superficial cortical (pial) vessels before they penetrate the cortex are modeled as a mesoscale vasculature. The validity of the present approach is demonstrated through comparisons with partially observed data from existing measurements of the vessel distributions on the brain surface, pathway fractal features, and vascular territories of the major cerebral arteries. Additionally, this validation provides some biological insights: (i) vascular pathways may form to ensure a reasonable supply of blood to the local surface area; (ii) fractal features of vascular pathways are not sensitive to overall and local brain geometries; and (iii) whole pathways connecting the upstream and downstream entire-scale cerebral circulation are highly dependent on the local curvature of the cerebral sulci.2020年06月, PLoS computational biology, 16(6) (6), e1007943, 英語, 国際誌[査読有り]研究論文（学術雑誌）
- This study investigated hemodynamic changes in the thoracic aorta and aortic arch branches before and after aortic valve replacement (AVR) by 4D-flow MRI in patients with aortic valve stenosis (AS). Thoracic 4D-flow MRI was performed in 10 AS patients before and after AVR (mean 27 ± 1.9 days). Fifteen aortic planes and 3 aortic arch branches planes were set to evaluate the mean volume flow rate in each plane during a cardiac cycle and the angle between the main flow direction in a specified plane and the axial direction of the aorta. We also focused on the distribution and magnitude of helicity density to evaluate the flow complexity. A significant increase in the volume flow rate after AVR was found in the ascending aorta (before 59.2 ± 8.7 mL/s vs after 77.3 ± 6.2 mL/s, P < 0.05) and the aortic arch branches (before 26.5 ± 2.8 mL/s vs after 35.8 ± 3.3 mL/s, P < 0.001). The flow angle significantly decreased in the ascending aorta (before 39.2 ± 2.7 degree vs after 25.2 ± 1.7°, P < 0.0001) and the arch aorta (before 19.3 ± 2.0 degree vs after 13.4 ± 0.9°, P < 0.001). The volume flow rate in the ascending aorta and the arch branches increased within 1 month after AVR, showing an increased blood supply to the upper body, including to the brain. The postoperative change was accompanied with an increased blood flow in the ascending aorta and a decreased flow complexity proximal to the arch branches.2020年, Seminars in thoracic and cardiovascular surgery, 32(1) (1), 25 - 34, 英語, 国際誌[査読有り]研究論文（学術雑誌）
- Proper coordination of gastric motor functions is required for healthy gastric emptying. However, pyloric function may be impaired by functional disorders or surgical procedures. Here, we show how coordination between pyloric closure and antral contraction affects the emptying of liquid contents. We numerically simulated fluid dynamics using an anatomically realistic gastrointestinal geometry. Peristaltic contractions in the proximal stomach resulted in gastric emptying at a rate of 3-8 ml min-1. When the pylorus was unable to close, the emptying rate increased to 10-30 ml min-1, and instantaneous retrograde flow from the duodenum to the antrum occurred during antral relaxation. Rapid emptying occurred if the pylorus began to open during the terminal antral contraction, and the emptying rate was negative if the pylorus only opened during the antral relaxation phase. Our results showed that impaired coordination between antral contraction and pyloric closure can result in delayed gastric emptying, rapid gastric emptying and bile reflux.2019年08月, Journal of the Royal Society Interface, 16(157) (157), 20190266 - 20190266, 英語, 国際誌[査読有り]研究論文（学術雑誌）
- Common practices to improve the ability to swallow include modifying physical properties of foods and changing the posture of patients. Here, we quantified the effects of the viscosity of a liquid bolus and patient posture on the bolus pathway and pharyngeal residue using a computational fluid dynamics simulation. We developed a computational model of an impaired pharyngeal motion with a low pharyngeal pressure and no pharyngeal adaptation. We varied viscosities from 0.002 to 1 Pa·s and postures from -15° to 30° (from nearly vertical to forward leaning). In the absence of pharyngeal adaptation, a honey-like liquid bolus caused pharyngeal residue, particularly in the case of forward-leaning postures. Although the bolus speed was different among viscosities, the final pathway was only slightly different. The shape, location, and tilting of the epiglottis effectively invited a bolus to two lateral pathways, suggesting a high robustness of the swallowing process.NEW & NOTEWORTHY Thickening agents are often used for patients with dysphagia. An increase in bolus viscosity not only reduces the risk of aspiration but also can cause a residual volume in the pharynx. Because information obtained from videofluoroscopic swallowing studies is only two-dimensional, measurement of pharyngeal residue is experimentally difficult. We successfully quantified the three-dimensional bolus pathway and the pharyngeal residual volume using computational modeling and simulation.2019年, American Journal of Physiology- Gastrointestinal and Liver Physiology,, 317(6) (6), G784-G792, 英語, 国際誌[査読有り]研究論文（学術雑誌）
- Cytoadhesion of red blood cells infected by Plasmodium falciparum (Pf-IRBCs) is predominantly found in postcapillary venules, rather than in arterioles. However, factors influencing this phenomenon remain unclear. Here, we conduct a systematic study using a numerical model coupling the fluid and solid mechanics of the cells and cellular environment with the biochemical ligand-receptor interaction. Our results show that, once a Pf-IRBC adheres to the vascular wall, the Pf-IRBC can withstand even arteriole shear stresses, and exhibits either rolling or firm adhesion. We also perform a simulation of the multistep process of cytoadhesion, consisting of flow, margination, capture, and rolling or firm adhesion. This multistep simulation suggests that a lower probability of contact with the vascular wall at high shear rates may diminish adherent Pf-IRBCs in the arterioles.CELL PRESS, 2017年09月, BIOPHYSICAL JOURNAL, 113(5) (5), 1163 - 1172, 英語[査読有り]研究論文（学術雑誌）
- The relationship between gastric motility and the mixing of liquid food in the stomach was investigated with a numerical analysis. Three parameters of gastric motility were considered: the propagation velocity, frequency, and terminal acceleration of peristaltic contractions. We simulated gastric flow with an anatomically realistic geometric model of the stomach, considering free surface flow and moving boundaries. When a peristaltic contraction approaches the pylorus, retropulsive flow is generated in the antrum. Flow separation then occurs behind the contraction. The extent of flow separation depends on the Reynolds number (Re), which quantifies the inertial forces due to the peristaltic contractions relative to the viscous forces of the gastric contents; no separation is observed at low Re, while an increase in reattachment length is observed at high Re. While mixing efficiency is nearly constant for low Re, it increases with Re for high Re because of flow separation. Hence, the effect of the propagation velocity, frequency, or terminal acceleration of peristaltic contractions on mixing efficiency increases with Re.AMER PHYSIOLOGICAL SOC, 2016年12月, AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY, 311(6) (6), G1114 - G1121, 英語[査読有り]研究論文（学術雑誌）
- A numerical analysis is presented of cell adhesion in capillaries whose diameter is comparable to or smaller than that of the cell. In contrast to a large number of previous efforts on leukocyte and tumor cell rolling, much is still unknown about cell motion in capillaries. The solid and fluid mechanics of a cell in flow was coupled with a slip bond model of ligand-receptor interactions. When the size of a capillary was reduced, the cell always transitioned to "bullet-like" motion, with a consequent decrease in the velocity of the cell. A state diagram was obtained for various values of capillary diameter and receptor density. We found that bullet motion enables firm adhesion of a cell to the capillary wall even for a weak ligand-receptor binding. We also quantified effects of various parameters, including the dissociation rate constant, the spring constant, and the reactive compliance on the characteristics of cell motion. Our results suggest that even under the interaction between P-selectin glycoprotein ligand-1 (PSGL-1) and P-selectin, which is mainly responsible for leukocyte rolling, a cell is able to show firm adhesion in a small capillary. These findings may help in understanding such phenomena as leukocyte plugging and cancer metastasis.AMER PHYSIOLOGICAL SOC, 2016年08月, AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, 311(2) (2), H395 - H403, 英語[査読有り]研究論文（学術雑誌）
- We developed a numerical model of the behavior of a red blood cell infected by Plasmodium falciparum malaria on a wall in shear flow. The fluid and solid mechanics of an infected red blood cell (Pf-IRBC) were coupled with the biochemical interaction of ligand-receptor bindings. We used the boundary element method for fluid mechanics, the finite element method for membrane mechanics, and the Monte Carlo method for ligand-receptor interactions. We simulated the behavior of a Pf-IRBC in shear flow, focusing on the effects of bond type. For slip bonds, the Pf-IRBC exhibited firm adhesion, tumbling motion, and tank-treading motion, depending on the applied shear rate. The behavior of catch bonds resembled that of slip bonds, except for a 'catch' state at high shear stress. When the reactive compliance decreased to a value in the order of 10(-2) nm, both the slip and catch bonds behaved like an ideal bond. Such bonds do not respond to the force applied to the bond, and the velocity is stabilized at a high shear rate. Finally, we compared the numerical results with previous experiments for A4- and ItG-infected cells. We found that the interaction between PfEMP1 and ICAM-1 could be a nearly ideal bond, with a dissociation rate ranging from 30 s(-1) to 100 s(-1).[GRAPHICS]TAYLOR & FRANCIS LTD, 2016年, SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS, 17(1) (1), 454 - 461, 英語[査読有り]研究論文（学術雑誌）
- We investigate flow in the stomach during gastric mixing using a numerical simulation with an anatomically realistic geometry and freesurface flow modeling. Because of momentum differences between greater and lesser curvatures during peristaltic contractions, timeaveraged recirculation is generated in the antrum, with retropulsive flow away from the pylorus and compensation flow along the greater curvature toward the pylorus. Gastric content in the distal stomach is continuously transported to the distal antrum by the forward flow of antral recirculation, and it is then mixed by the backward retropulsive flow. Hence, the content inside the antral recirculation is well mixed independently of initial location, whereas the content outside the recirculation is poorly mixed. Free-surface modeling enables us to analyze the effects of posture on gastric mixing. In the upright, prone, and right lateral positions, most of the antrum is filled with content, and the content is well mixed by antral recirculation. In contrast, in the supine and left lateral positions, most of the content is located outside antral recirculation, which results in poor mixing. The curved, twisted shape of the stomach substantially supports gastric mixing in fluid mechanical terms. © 2013 the American Physiological Society.2013年, American Journal of Physiology - Gastrointestinal and Liver Physiology, 304(5) (5), G536 - G542, 英語[査読有り]研究論文（学術雑誌）
- 第35回バイオフロンティア講演会, 2024年12月腸壁の収縮弛緩と重積現象の関係
- 第35回バイオフロンティア講演会, 2024年12月虹彩の収縮ヒダ形成の流体構造連成解析，第35回バイオフロンティア講演会
- 第35回バイオフロンティア講演会, 2024年12月生理的臍帯ヘルニアの維持に関する数値解析
- 第35回バイオフロンティア講演会, 2024年12月流れ場に応じた血管の変形が血管網構築過程に及ぼす影響の計算力学的検討
- 第35回バイオフロンティア講演会, 2024年12月細胞膜拡大による神経突起形成の数値解析フレームワークの開発
- 第38回数値流体力学シンポジウム, 2024年12月有機無声破裂音の数値流体力学解析と音響解析
- 第38回数値流体力学シンポジウム, 2024年12月磁性液滴によるマイクロ流路内の竜東輸送に関する流体磁場連成解析
- 第14回計算力学シンポジウム, 2024年12月磁性液滴挙動の数値解析[招待有り]
- 第37回計算力学講演会, 2024年10月中腸と腸間膜の力学的相互作用が中腸発生に及ぼす影響
- 第37回計算力学講演会, 2024年10月粘性環境中で自発的に変形するシート状組織の流体構造連成解析
- IWACOM-VI, 2024年09月Fluid-flow-induced wrinkling of a capsule membrane: An isogeometric analysis
- IWACOM-VI, 2024年09月Folds emerging from fluid-structure interaction of sheets with surrounding fluids
- 第29回計算工学講演会, 2024年06月弾性管の蠕動運動により生じる管内流れのアイソジオメトリック境界要素解析
- 第29回計算工学講演会, 2024年06月粘性流体との相互作用による薄膜の変形の流体構造連成解析
- 第29回計算工学講演会, 2024年06月アイソジオメトリック境界要素法による超弾性体シートの沈降挙動解析
- 第29回計算工学講演会, 2024年06月細胞膜の拡大による樹状突起スパイン形成のアイソジオメトリック解析
- 第34回バイオフロンティア講演会, 2023年12月数値計算による中腸の形態形成における突出と回転のメカニズムの力学的な検討
- 第34回バイオフロンティア講演会, 2023年12月能動的な収縮を考慮した消化管の蠕動運動による内容物輸送の流体ー構造連成解析
- 第34回バイオフロンティア講演会, 2023年12月局所的に剛性の異なる領域を持つ管の弛緩と腸重積症との関係
- 第34回バイオフロンティア講演会, 2023年12月周囲組織の力学的な拘束を考慮した血管の蛇行の数値解析
- 第34回バイオフロンティア講演会, 2023年12月流体-構造連成解析と深層学習を用いた血管を流れる赤血球の3次元形状再構築手法の開発
- 第37回数値流体力学シンポジウム, 2023年12月境界積分法を用いた磁性液滴の変形・分裂の3次元数値解析
- 第37回数値流体力学シンポジウム, 2023年12月アイソジオメトリック境界要素法による超弾性シートとストークス流れの数値流体構造連成解析
- APBiomech2023, 2023年11月Self-Organized Patterns of Ferrofluid Droplets in Wall-Bounded Shear Flow
- APBiomech2023, 2023年11月Isogeometric Boundary Element Analysis of Wrinkling and Creasing of a Capsule Membrane in a Shear Flow
- APBiomech2023, 2023年11月Development of A 3D Reconstruction Method for Red Blood Cell Shapes by Deep Learning and Fluid-Structure Interaction Analysis
- APBiomech2023, 2023年11月A Suppression Effect of a Magnetic Field on Breakup of a Ferrofluid Droplet in Simple Shear Flow
- APBiomech2023, 2023年11月Growth-Induced Fold Formation of a Sheet-Like Tissue in a Viscous Fluid: An Isogeometric Boundary Element Analysis
- APBiomech2023, 2023年11月Numerical Analysis of the Midgut Elongation Under the Effect of the Mesentery
- 第36回計算力学講演会, 2023年10月ストークス流れの中で変形する超弾性シートの数値解析
- 第36回計算力学講演会, 2023年10月腸重積症と関連した小腸における重積現象の解明
- AJKFED 2023, 2023年07月The shape of the vocal tract that generates the aspirated voiceless alveolar plosive [th]
- AJKFED 2023, 2023年07月A fluid-structure interaction analysis of growth-induced fold formation of a sheet in a viscous fluid
- AJKFED 2023, 2023年07月A numerical analysis of fluid propulsion using ferrofluid droplet in microchannel
- AJKFED 2023, 2023年07月A computational method for 3D reconstruction of red blood cell shapes using deep learning and fluid-structure interaction analysis
- 第28回計算工学講演会, 2023年06月粘性流体中で成長する薄膜の変形のアイソジオメトリック解析
- 第28回計算工学講演会, 2023年06月磁性流体を用いたマイクロ流路内の流れの駆動
- 18th International Symposium on Computer Methods In Biomechanics and Biomedical Engineering (CMBBE2023), 2023年05月Computational modeling of the cerebrospinal fluid flow: effect of cilia-induced velocity[招待有り]
- The 11th International Conference on Multiphase Flow, 2023年04月Rheology of ferrofluid droplet suspension in wall-bounded shear flow
- The 11th International Conference on Multiphase Flow, 2023年04月A 3D numerical analysis for a effect of a magnetic field on breakup of a ferrofluid droplet in simple shear flow
- 第33回バイオフロンティア講演会, 2022年12月機械学習を用いた嚥下造影検査による誤嚥の検出
- 第33回バイオフロンティア講演会, 2022年12月血液中における好中球と血小板の相互作用に関する数値シミュレーション
- 第33回バイオフロンティア講演会, 2022年12月周囲組織の力学的な拘束を考慮した血管変形の流体-構造連成解析
- 第33回バイオフロンティア講演会, 2022年12月生体組織の成長にともなう中腸の形態形成のアイソジオメトリック解析
- 第33回バイオフロンティア講演会, 2022年12月孤立収縮波の蠕動運動によるべき乗則流体の輸送 ： 格子ボルツマン法に基づく数値解析
- 第33回バイオフロンティア講演会, 2022年12月喉頭蓋翻転異常によって引き起こされる嚥下障害の 数値流体計算を用いた誤嚥経路の解析
- 第36回数値流体力学シンポジウム, 2022年12月単純せん断流中における分裂を伴う磁性液滴の3次元磁場-流体連成解析
- 日本流体力学会年会2022, 2022年09月脳室内流れにおける繊毛の影響について
- 9th World Congress of Biomechanics, 2022年07月A computational model of leukocyte rolling
- 9th World Congress of Biomechanics, 2022年07月A computational fluid dynamics analysis for high-flow nasal cannula system using lattice Boltzmann method
- 9th World Congress of Biomechanics, 2022年07月Escape of small capsules from large capsules aligned in confined shear flow: a computational study[招待有り]
- 9th World Congress of Biomechanics, 2022年07月Development of deep learning framework for videofluoroscopy
- 9th World Congress of Biomechanics, 2022年07月Peristaltic pumping of a power-law fluid: a lattice Boltzmann study
- 9th World Congress of Biomechanics, 2022年07月Relationship between peristaltic frequency and gastric emptying: a computational fluid dynamics analysis
- 第34回バイオエンジニアリング講演会, 2022年06月局所的な膜面積の増加にともなう細胞膜突出のアイソジオメトリック解析
- 第34回バイオエンジニアリング講演会, 2022年06月胃内流動の数値流体力学解析：蠕動収縮の発生頻度と振幅の影響
- 第32回バイオフロンティア講演会, 2022年01月格子ボルツマン法による高流量鼻腔カニューラの数値流体力学解析
- 第32回バイオフロンティア講演会, 2022年01月流れの中の赤血球に対するIGA-LBM
- The 11th Asian-Pacific Conference on Biomechanics, 2021年12月Local mesh refinement for cumulant lattice Boltzmann method: a level conversion method
- The 11th Asian-Pacific Conference on Biomechanics, 2021年12月Computational fluid dynamics analysis of effect of ciliary motion on cerebrospinal fluid flow
- The 11th Asian-Pacific Conference on Biomechanics, 2021年12月Isogeometric hyperelastic analysis for cell membrane protrusion
- The 11th Asian-Pacific Conference on Biomechanics, 2021年12月Effect of peristaltic frequency on gastric emptying: a simulation study
- The 11th Asian-Pacific Conference on Biomechanics, 2021年12月Coupling isogeometric analysis with lattice Boltzmann method for simulating red blood cells in flows
- The 11th Asian-Pacific Conference on Biomechanics, 2021年12月The behavior of a ferrofluid droplet in external magnetic fields under oscillating shear flow
- The 11th Asian-Pacific Conference on Biomechanics, 2021年12月Cumulant lattice Boltzmann method for peristaltic transport of power-law fluids
- The 11th Asian-Pacific Conference on Biomechanics, 2021年12月A computational model of cell adhesion and migration under fluid shear stress
- 第34回計算力学講演会, 2021年09月嚥下の三次元数値シミュレーション：嚥下の冗長性と咽頭圧の関係
- 第33回バイオエンジニアリング講演会, 2021年06月嚥下流動の数値流体力学解析
- 第26回計算工学講演会, 2021年06月カプセルの流動計算のためのIGA-LBM
- The 3rd International Conference on Computational Engineering and Science for Safety and Environmental Problems (COMPSAFE2020), 2020年12月Development of a CFD simulator of whole cerebral blood flow
- 第25回計算工学講演会, 2020年06月流体中の膜挙動に対するisogeometric流体構造連成手法の開発
- 第32回バイオエンジニアリング講演会, 2019年12月全脳循環血流シミュレータの開発
- The 10th Asian-Pacific Conference on Biomechanics, 2019年11月Numerical analysis of large-scale cerebral artery blood flow using patient-specific cerebrovascular models
- 第32回計算力学講演会, 2019年09月脳血管網モデリングと全脳循環血流場の数値計算
- 第32回計算力学講演会, 2019年09月大脳動脈の被験者個別モデルを用いた大規模血流解析
- 第32回計算力学講演会, 2019年09月ネットワーク構造と液体膜の連成計算
- The 29th International Symposium on Cerebral Blood Flow, Metabolism and Function, 2019年07月Development of a numerical model of whole-scale cerebral circulation
- 6th International Conference on Computational and Mathematical Biomedical Engineering, 2019年06月Modeling cerebral vasculatures for analysis of the whole cerebral circulation
- 第24回計算工学講演会, 2019年05月全脳循環血流場の大規模並列シミュレーション
- 第31回格子ボルツマンの基礎と応用に関する研究会（LBM研究会）, 2019年05月格子ボルツマン法による生体流れの数値計算[招待有り]
- 第31回バイオエンジニアリング講演会, 2018年12月胃内容物の撹拌・排出の数値シミュレーション
- 第31回バイオエンジニアリング講演会, 2018年12月数値力学試験によるフィブリン凝集塊の巨視的力学特性の評価
- 第32回数値流体力学シンポジウム, 2018年12月実形状モデルを用いた胃内流動の数値計算
- The 71st Annual Meeting of The APS Division of Fluid Dynamics, 2018年11月Mesoscopic Protofibril Aggregation Model for Numerical Analysis of Fibrin Clot Formation
- 第31回計算力学講演会, 2018年11月胃の撹拌・排出の計算力学解析
- 第29回バイオフロンティア講演会, 2018年10月フィブリン凝集塊形成の数値シミュレーション：個々の凝集条件が凝集塊構造に与える影響
- 第29回バイオフロンティア講演会, 2018年10月全脳循環血流場の数値シミュレーションに向けた脳血管構造モデリング
- 日本機械学会2018年度年次大会, 2018年09月, 日本語微小循環におけるマラリア感染赤血球の接着挙動の数値解析
- The 8th World Congress of Biomechanics, 2018年07月, 英語, 国内会議Relationship between gastric wall motility and mixing of liquid foods in the stomachポスター発表
- The 8th World Congress of Biomechanics, 2018年07月, 英語, 国際会議Numerical simulation of cytoadhesion of red blood cells infected by Plasmodium falciparum口頭発表（一般）
- 第23回計算工学講演会, 2018年06月, 日本語流体力学-固体力学-生化学の連成計算による微小循環におけるマラリア感染赤血球の挙動解析
- 日本耳鼻咽喉科学会会報, 2018年04月, 日本語, (一社)日本耳鼻咽喉科学会重力に依存した嚥下運動の数値流体力学シミュレーションの開発
- 第30回計算力学講演会, 2017年09月, 日本語胃における蠕動運動と流れの関係についての一考察
- 第30回計算力学講演会, 2017年09月, 日本語マラリア感染赤血球の接着挙動の数値計算
- 第22回計算工学講演会, 2017年06月, 日本語胃から十二指腸への食物排出の数値計算
- 第29回バイオエンジニアリング講演会, 2017年01月, 日本語胃内部の固体粒子挙動の数値計算
- 第29回バイオエンジニアリング講演会, 2017年01月, 日本語胃壁の運動機能と胃内容物攪拌の関係
- The 16th International Conference on Biomedical Engineering, 2016年12月, 英語Development of a biomechanical model of cell behavior subjected to cyclic stretch
- The 16th International Conference on Biomedical Engineering, 2016年12月, 英語Relationship between peristaltic contraction and gastric mixing
- The 69th Annual Meeting of The APS Division of Fluid Dynamics, 2016年11月, 英語Numerical analysis of cell adhesion in capillary flow
- 日本流体力学会年会2016, 2016年09月, 日本語胃における蠕動運動の流れの数値流体力学解析
- 第28回バイオエンジニアリング講演会, 2016年01月, 日本語蠕動運動と胃内容物攪拌の関係
- 第26回バイオフロンティア講演会, 2015年10月, 日本語細胞骨格運動の数値シミュレーション
- The 3rd International Workshops on Advances in Computational Mechanics, 2015年10月, 英語Graphics processing unit computing of cellular flow and adhesion in microvessels
- The 8th Asian-Pacific Conference on Biomechanics, 2015年09月, 英語Development of a Numerical Model of Cytoskeleton Dynamics
- The 8th Asian-Pacific Conference on Biomechanics, 2015年09月, 英語Clarification of Relationship between Gastric Mixing and Movement of Wall
- The 8th Asian-Pacific Conference on Biomechanics, 2015年09月A numerical simulation of cytoadhesion and rosette formation of red blood cells infected by malaria
- 第20回計算工学講演会, 2015年06月, 日本語胃内容物攪拌の数値計算：胃壁の運動の影響
- 日本機械学会東北支部第50期総会・講演会, 2015年03月, 日本語細胞骨格の運動の計算力学モデルの開発
- 第27回バイオエンジニアリング講演会, 2015年01月, 日本語胃内のせん断応力の数値解析
- Internationnal Symposium on Integrated Nanobiomechanics, 2014年09月, 英語Shear Stress Distribution in the Stomach
- The 4th Japan-Switzerland workshop on biomechanics, 2014年09月, 英語Modeling of flow in the stomach
- Advances in Computational Fluid-Structure Interaction and Flow Simulation, 2014年03月, 英語How Does Gastric Mixing Proceed over Minutes?
- 第17回計算工学講演会, 2012年05月, 日本語実形状モデルを用いた胃内容物攪拌の数値流体力学解析
- 第24回バイオエンジニアリング講演会, 2012年01月, 日本語GPUを用いた胃内容物攪拌の3次元計算
- 5th East Asian Pacific Student Workshop on Nano-Biomedical Engineering, 2011年12月, 英語A numerical computation on gastric mixing using GPU
- 第24回計算力学講演会, 2011年10月, 日本語嚥下造影画像に基づく嚥下の計算力学解析
- 第24回計算力学講演会, 2011年10月, 日本語胃内容物攪拌の数値計算
- International Conference on BioTribology, 2011年09月, 英語Swallowing simulation based on videofluorography
- 第23回バイオエンジニアリング講演会, 2011年01月, 日本語胃内容物攪拌の数値流体力学モデルの開発
- 第23回バイオエンジニアリング講演会, 2011年01月, 日本語嚥下造影画像に基づく嚥下の数値シミュレーション
- 6th World Congress of Biomechanics, 2010年08月, 英語Analysis of swallowing motion based on videofluorography
- 6th World Congress of Biomechanics, 2010年08月, 英語A numerical study on fluid motion in the stomach
- 日本機械学会東北支部第45期総会・講演会, 2010年03月, 日本語粒子法を用いた胃内容物攪拌の数値シミュレーション
- 第21回バイオフロンティア講演会, 2010年01月, 日本語胃内容物流れの数値シミュレーション：内容物量の影響
- 第20回バイオフロンティア講演会, 2009年11月, 日本語嚥下造影画像に基づく食塊・喉頭蓋の運動解析
- 日本機械学会東北支部第44期総会・講演会, 2009年03月, 日本語嚥下造影画像を用いた嚥下メカニズムの力学的考察
■ 共同研究・競争的資金等の研究課題
- 日本学術振興会, 科学研究費助成事業, 挑戦的研究(萌芽), 神戸大学, 2023年06月 - 2026年03月, 研究代表者直腸切除手術後における排便機能障害の力学的メカニズム解明
- 日本学術振興会, 科学研究費助成事業, 基盤研究(B), 神戸大学, 2022年04月 - 2026年03月磁性液滴の多体制御理論構築によるマイクロ流体アクチュエータの開発
- 日本学術振興会, 若手研究, 若手研究, 神戸大学, 2019年04月 - 2022年03月, 研究代表者実形状数値計算による嚥下過程の力学メカニズム解明と新しい嚥下機能の評価法の提案数値流体力学と医用画像を用いて，三次元実形状の嚥下流動計算モデルを構築した．咽頭運動の適応が欠落すると咽頭圧が十分に生じず，高粘度の食塊の嚥下時や前傾姿勢での嚥下時に食塊の残留が多くなり，誤嚥リスクが増加することを示した．また，咽頭収縮が低下することで粘度の高い食塊において嚥下が困難になり，安定な嚥下のためには咽頭収縮による咽頭圧が重要であることが示唆された．競争的資金
研究シーズ
■ 研究シーズ- 生体流れや磁性流体の計算流体力学シーズカテゴリ：ライフサイエンス, ものづくり技術（機械・電気電子・化学工業）研究キーワード：計算バイオメカニクス, 数値流体力学, 嚥下, 磁性流体研究の背景と目的：体の中の流れは、生命機能や疾病と密接に関係していますが、生体内の流れを実験的に観察するのは困難です。また、磁性流体は外部からの磁場で挙動をコントロールすることによって薬剤輸送など医用分野での応用やマイクロデバイスへの応用が期待できます。本研究では、力学法則に基づいた数値シミュレーションによって生命の機能や病理解明、磁性流体の制御方法の開発を目指しています。研究内容：嚥下とは食物を飲み込む動作のことであり、多くの器官が連動する複雑な運動です。加齢や疾患などで嚥下の機能が低下する嚥下障害では、食物が器官側へ流入する誤嚥が生じ、肺炎の原因となります。医用画像をもとに咽頭の収縮力が低下した嚥下障害の計算力学モデルを構築し、液体食物の粘度や嚥下姿勢によって嚥下動態がどのように変化するかを明らかにしました。 磁性流体は、外部から磁場を与えることによって形や性質を大きく変えることができる物質です。磁性流体の挙動をうまくコントロールすることができれば、医用分野での応用やマイクロデバイスへの応用などが期待できます。磁性流体の基本的な性質を調べるために、せん断流れ中の磁性液滴が外部磁場を受けたときに磁場の方向や強さによって変形量やレオロジー特性がどのように変化するかを数値計算によって明らかにしました。
期待される効果や応用分野：さまざまな食塊の嚥下をコンピュータ上でシミュレーションすることが可能となり、将来的に嚥下の診断や治療への応用が期待されます。 磁性液滴は、外部磁場をあたえることで挙動を非接触に変化させることが可能であり、コントロール方法を開発することで医用分野での応用やマイクロデバイスへの応用が期待できます。関係する業績：Ohta J, Ishida S, Kawase T, Katori Y, Imai Y, Am J Physiol Gastrointest Liver Physiol 317, G784-G792 (2019) Ishida S, Matsunaga D, Phys Rev Fluids 5, 123603 (2020)